Internal combustion engine manufacturers are constantly seeking to increase power output and fuel efficiency of their products. One method of generally increasing efficiency and power is to reduce the oscillating mass of an engine, e.g., of the pistons, connecting rods, and other moving parts of the engine. Efforts to increase engine power and/or efficiency also may also result in an increase in pressure and/or temperature within the combustion chamber during operation.
Power in an engine is typically transferred from a piston reciprocating within a cylinder bore via a connecting rod linked to the piston by way of a piston pin received within a corresponding pin bore of the piston. Thus, as the air/fuel mixture expands within the combustion chamber, the piston is forced downward, pushing the connecting rod downward. The connecting rod is linked with a crankshaft, which is rotated as the piston reciprocates.
Pistons are typically provided with skirts or other cylindrical surfaces configured to slide along corresponding cylinder bore surfaces of an engine. The lateral movement of the lower or large end of the connecting rod results in the connecting rod being angled with respect to the piston/cylinder axis as the piston is forced downward by combustion pressure. Accordingly, one side of the piston, referred to as the “thrust side,” typically experiences a greater load against the cylinder bore, compared with the opposite or “anti-thrust side” of the piston. This imbalance causes vibrations such as secondary motions, which tends to cause cavitation of cylinder bore surfaces.
Accordingly, there is a need for a piston that addresses the above problems.